<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        /*标签选择器*/
        span{
            font-weight: bolder;
        }

        /*id选择器*/
        #i1{
            color:blue;
        }

        /*类选择器*/
        .item{
            color: red;
        }

        /*通用选择器*/
        *{
            background-color: yellow;
        }
    </style>
</head>
<body>
    <span>bbbbb</span>
    <p>hello</p>
    <p id="i1">hello</p>
    <p class="item">hello</p>
    <p class="item">hello</p>
    <p class="item">hello</p>
    <p class="item">hello</p>
    <p class="item">hello</p>
</body>
</html>